Apple's iPhone Duo Arrives as Foldables Settle on One Shape
Apple's first foldable iPhone, the iPhone Duo, goes on sale October 23, with pre-orders opening a week earlier. Apple unveiled the device on September 9, 2026. Apple is already selling the iPhone 18 Pro alongside it. Engadget
The Duo is passport-shaped, short and wide when folded, and priced at $1,999. It uses Apple's A20 Pro chip, the main processor for computing and graphics. Apple announced the iPhone 18 Pro and iPhone 18 Pro Max at the same September event, and published a Newsroom release titled "Apple unveils iPhone Duo." Reuters
Xiaomi, Oppo, Motorola and Samsung have all explored foldable phones resembling the iPhone Duo. Most competitors now have a foldable device in passport format. The closest dimensional match is the Xiaomi 18 Fold, which arrived just days before the iPhone Duo was unveiled and went on sale across China after Apple's September launch. Both phones have a 7.6-inch inner screen and a 5.4-inch outer screen with the same aspect ratio, the proportional shape of the display.
The divergence is in mass, thickness, optics and availability. The Xiaomi 18 Fold weighs 219 grams. The iPhone Duo weighs 254 grams. When folded, the Xiaomi 18 Fold measures 117.8 x 83.6mm with a thickness of 10.68mm. The Xiaomi 18 Fold has three rear camera lenses against two rear cameras on the iPhone Duo. It starts at 10,999 yuan (about $1,640) and will only be available in China for now.
Samsung has iterated on a wider cover, the outer screen you use when the phone is shut. The Samsung Galaxy Z Fold8 has a 7.6-inch inner screen and a 5.5-inch outer screen in a wider passport shape. It has a straighter design with no curved corners. It launched in August and starts at $1,900, $100 less than the iPhone Duo starting price. Engadget's review gave the Samsung Galaxy Z Fold8 8.9 out of 10. The Samsung Galaxy Z Fold8 Ultra retains a square-ish shape.
OPPO's current work centers on crease control and pen input. The OPPO Find N6 is a foldable flagship phone featuring Zero-Feel Crease, OPPO's hinge system for a flatter inner screen with less visible fold line. It features a 200MP Hasselblad camera. It is paired with the OPPO AI Pen. OPPO describes the Find N6 as its latest flagship foldable. It is certified to stay flat even after 600,000 folds. It reduces long-term crease formation by up to 82%. OPPO
The prior generation remains relevant on thinness and charging. The OPPO Find N5 is an 8.93mm ultra-slim foldable phone. It has a 5600mAh battery, a measure of charge capacity. It supports 80W SUPERVOOC charging and 50W AIRVOOC charging, OPPO's wired and wireless fast-charging systems. It is powered by the Snapdragon 8 Elite chip. OPPO's first foldable flagship smartphone was the OPPO Find N.
Xiaomi's weight position reflects several hinge and materials generations. The Xiaomi MIX Fold 4 weighs 226g and uses Xiaomi's proprietary hinge 2.0. The Xiaomi MIX Flip weighs 192g with a folded thickness of 15.99mm. The Xiaomi Mix Fold 3 is rated for up to 500,000 folds and uses ultra-high-strength steel rated at 1800MPa, a pressure rating for how much stress the steel can take. The Xiaomi MIX Fold 4 features the Xiaomi Guardian Structure using S2 premium glass fiber on an aramid fiber and ceramic base. The Xiaomi 18 Fold is lighter than all previous Xiaomi foldable smartphones.
Foldable phones are on track to account for less than 3% of the global smartphone market in 2026, according to IDC.
The broader context here is convergence rather than invention. Hinge cycle ratings, inner screen size and outer screen aspect ratio have stabilized across vendors after years of experimentation. Weight tells part of the story. A 35-gram delta matters on a device held open for reading and multitasking. Crease behavior matters more. OPPO's flatness certification and Xiaomi's fold ratings set the durability baseline that carriers and enterprise fleets will use when evaluating any new entrant.
In my view, the practical upside is for developers and power users. A 7.6-inch inner panel in passport format is now common across Xiaomi, Samsung and Apple. That stability makes it easier to target large-screen layouts, stylus workflows and sustained multitasking without betting on a single vendor's geometry. I have watched my own children treat folding screens less as novelties and more as pocketable tablets. If that habit spreads, the Duo's contribution may be to normalize the form for Western app ecosystems that have so far treated it as an edge case.
